In the medical health professions, a health hazard commonly known as the "needle stick" exists. The hazard exists because needles or cannula employed in the profession do not have safety features to prevent a used needle or cannula from accidentally sticking or puncturing the flesh of medical, clean up and/or other personnel before the used needle or cannula is finally disposed of.
The needle stick hazard, of course, incurs the possibility of transmitting infectious diseases such as hepatitis, AIDS, herpes and the like through needles or cannula which have become contaminated through prior usage.
A wide variety of devices in the prior art are designed to prevent needle stick injuries in the use of hypodermic needles. There are two basic types employed in this area. The first type may generally be described as an attached but retractable covering means or a sliding sheath. Typical of this embodiment are Fox, U.S. Pat. No. 4,695,274; Dombrowski, U.S. Pat. No. 4,790,828; Hagen, U.S. Pat. No. 4,735,618 and Nelson et al., U.S. Pat. No. 4,659,330.
The second type generally consists of a plunger or piston which operates to both expulse medicament and to selectively engage the needle carrying base to relocate the needle inside the syringe upon withdrawal of the plunger or piston. These are described in, inter alia, Haber et al., U.S. Pat. No. 4,710,170; Vining et al., U.S. Pat. No. 4,507,117; DeLuccia, U.S. Pat. No. 4,675,005; Haller, U.S. Pat. No. 4,692,156 and Gloyer et al., U.S. Pat. No. 4,747,830.
The prior art also describes devices aimed at preventing needle-stick injuries in intravenous catheters.
Jagger et al., U.S. Pat. No. 4,592,744 broadly describes safety venipuncture devices having a needle retracting means, which may include intravenous devices as well as hypodermic needles and vacuum tube phlebotomy systems. The patentee generally teaches a needle retracting means comprising withdrawing a hub located at the rear of the device, which is also connected to the needle assembly. Thus, upon withdrawing the hub, the needle assembly is relocated to a protected interior portion of the device.
McDonald, U.S. Pat. No. 4,834,718 discloses an intravenous catheter apparatus designed to aid in protecting a clinician from accidental puncture. The patentee teaches a means for withdrawing the needle from a patient's body into a protective housing without exposing the needle during any intermediate stage of the process. A handle means, located at the rear of the device, which is secured to the needle for manually pushing the needle forward to effect the puncture and thereafter for pulling the needle rearwardly in order to withdraw it from the puncture site into a protective housing.
Similarly, Luther et al., U.S. Pat. No. 4,762,516 disclose a needle catheter protector wherein the needle assembly is withdrawn into a protective housing by retracting an outer portion of the housing to which the needle is attached, so that the needle is locked within a forward bore element.
All of the above catheter protectors suffer from the need to withdraw the needle from a means located at the rear of the device. This rearward means requires the user to employ two hands to withdraw the needle into the protective housing. While one hand is on the housing and the other is withdrawing the needle from the rear of the device, the needle is likely to be moved and can either puncture the rear wall of the vein or slip out of the vein. In either instance, the whole process of inserting the catheter must be repeated. It would therefore constitute a notable advance in the state of the art if a safety catheter could be developed in which the withdrawal means could be operated with one hand, leaving the second hand free to ensure that the needle remains securely in the vein during withdrawal.
Furthermore, the use of a housing or sliding sheath removal means located at the rear of device presents disposal problems. All of the prior art safety catheters teach a device which when the needle is retracted is twice as long as the device when the needle is not retracted, due to the use of a sliding sheath to withdraw the needle. In this day and age of concern about and the expense of disposing of hospital waste, particularly needles, it is highly desirable to produce a more compact and easily disposable safety catheter.
Also to be mentioned is Alvarez, U.S. Pat. No. 4,170,993 which describes an intravenous assembly designed to aid in the emplacement of the needle within the patient's blood vessel.